Merge pull request #29 from abettermap/27.slim-geojson

Optimize GeoJSON

automation/shp-to-geojson.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+
+# -----------------------------
+# shp-to-geojson.sh
+# Convert shapefiles to GeoJSON
+# -----------------------------
+
+SOURCE_SHP="${1:-cerp/static/VoterPrecinct.shp}"
+DEST_GEOJSON="${2:-cerp/static/VoterPrecinct.geojson}"
+FIELDS_TO_KEEP="PRECINCT,SENATEDIST,HOUSEDIST,COMMDIST,UPDATEDATE"
+TOLERANCE=0.00015 # smaller decimal = higher precision
+
+# ogr2ogr cannot overwrite GeoJSON?
+rm -f $DEST_GEOJSON
+
+# Convert shp to geojson
+ogr2ogr \
+  -f "GeoJSON" \
+  -lco COORDINATE_PRECISION=5 \
+  -simplify $TOLERANCE \
+  -select $FIELDS_TO_KEEP \
+  "$DEST_GEOJSON.tmp" \
+  $SOURCE_SHP
+
+# Check if `json-minify` exists, install if not
+if ! type json-minify &> /dev/null; then
+  npm i -g json-minify
+fi
+
+# Minify GeoJSON
+json-minify "$DEST_GEOJSON.tmp" > $DEST_GEOJSON
+
+# Delete temp file
+rm "$DEST_GEOJSON.tmp"
+
+# topojson example
+# topojson $DEST_GEOJSON > "$DEST_GEOJSON.topojson" -p